2022 Developer Survey is open! Take survey.

# Questions tagged [number]

A competition to solve a particular problem through the usage and manipulation of numbers.

1,212 questions
Filter by
Sorted by
Tagged with
96 views

### Previous Fibonacci number

The sequence of Fibonacci numbers is defined as follows: $F_0 = 0 \\ F_1 = 1 \\ F_n = F_{n-1} + F_{n-2}$ Given a Fibonacci number, return the previous Fibonacci number in the sequence. You do not ...
2k views

### There's more than one way to skin a set

Given a set of positive integers $S$, output the set of all positive integers $n$ such that $n$ can be made by summing a subset of $S$ in more than one different way, i.e., that are ...
37k views

### Fibonacci function or sequence

The Fibonacci sequence is a sequence of numbers, where every number in the sequence is the sum of the two numbers preceding it. The first two numbers in the sequence are both 1. Here are the first ...
28k views

### Largest Number Printable

Your goal is to write a program that prints a number. The bigger the number, the more points you'll get. But be careful! Code length is both limited and heavily weighted in the scoring function. Your ...
5k views

### Find the highest unique digit

Surprisingly we haven't had a simple "find the highest digit" challenge yet, but I think that's a little too trivial. Given input of a non-negative integer, return the highest unique (ie not ...
9k views

### Output the sign

Given a number N, output the sign of N: If N is positive, output 1 If N is negative, output -1 If N is 0, output 0 N will be an integer within the representable range of integers in your chosen ...
14k views

### Print 0 to 100 without 1-9 characters

Print 0 to 100 without using characters 1,2,3,4,5,6,7,8,9 in your code. Seperator of numbers can be comma, whitespace or newline. Shortest code wins.
6k views

### How long is my number?

Challenge Given an integer $Q$ in the range $-2^{100} ≤ Q ≤ 2^{100}$, output the number of digits in that number (in base 10). Rules Yes, you may take the number as a string and find its length. ...
2k views

### Output two numbers (Robbers' thread)

This is the robbers' thread to a cops-and-robbers challenge. Click the link to find the cops' thread. In the cops' thread of this challenge, answerers will be writing programs which output two ...
3k views

### Find the weight of five apples

Problem John bought 5 apples. You are given the weights of every group of four apples, and must then find the weights of the apples themselves. For example, if all apples without the first one weigh ...
2k views

### Calculate the area of a regular polygon

Task Given an integer, n, where 3 <= n < 2^32, calculate the area of a regular n-gon, ...
15k views

### Count up forever

Write a program that counts up forever, starting from one. Rules: Your program must log to STDOUT or an acceptable alternative, if ...
3k views

### Sort by Multiplying

You should write a program or function that given a list of positive integers multiplies each element with the smallest positive integer possible to create a strictly increasing list. For example if ...
3k views

### Find the next 1-sparse binary number

A positive integer N is K-sparse if there are at least K 0s between any two consecutive 1s in its binary representation. So, the number 1010101 is 1-sparse whereas 101101 is not. Your task is to ...
2k views

### How many times do I break my own rule?

Introduction: In my recent Strikethrough the Word Search List challenge I mentioned the following: When I do the word-search puzzles, I (almost) always go over the words in order, and strike them ...
2k views

### Palindromic Powers

Powers We define an important power as a number that can be represented as $x^y$ where $x ≥ 2$ and $y ≥ 2$. Palindrome We define an ...
1k views

### Bounce-modulo two numbers

The graph of the modulo operation ($y = x \mod k$) looks like this: This is a very useful function, as it allows us to create "wrapping" behavior. However, it is very cumbersome when I want to use ...
534 views

### Batt to the Basics

One of your acquaintances has a hobby of making make-shift electrical gadgets using various types of batteries. However, since they're thrifty, they want to use as few batteries as possible for their ...
2k views

### Music with pi and e

Because I forgot to celebrate Pi Day (14.3), let's celebrate with $\pi$, $e$ (Euler's number) and music! Challenge No, we don't have time to eat a pi-pizza, let's make a program. What you need is ...
58k views

### Is this number a prime?

Believe it or not, we do not yet have a code golf challenge for a simple primality test. While it may not be the most interesting challenge, particularly for "usual" languages, it can be nontrivial in ...
2k views

### ASCII-Art n'th Root

Challenge: Given two integers $a$ and $b$, with lengths $A=length(a), B=length(b)$, output an ASCII-art of the $a^{th}$ root of $b$, including the answer rounded to $A$ amount of decimal ...
6k views

### Numbers with Rotational Symmetry

Given an integer, output a truthy value if it is the same upside-down (rotated 180°) or a falsy value otherwise. 0, 1, and <...
3k views

### Range, Reverse, Sum!

Given a positive integer n as input, output the reversed range sum of n. A reversed range sum is created by making an inclusive range up to n, starting with 1 and including n, reversing each of the ...
2k views

### Reverse Maths Cycles

Inspired by this In the linked challenge, we are asked to apply addition to the elements of the original and the reverse of the input array. In this challenge, we are going to make it slightly more ...
658 views

### Rounding a range

You have a line with two endpoints a and b (0 ≤ a < b) on a 1D space. When ...
8k views

### Covering a Skyline with brush strokes

Given a non-negative integer skyline height list, answer how many uninterrupted 1-unit-high horizontal brush strokes are needed to cover it. [1,3,2,1,2,1,5,3,3,4,2]...
3k views

### Rotate a number

Given a positive number n, rotate its base-10 digits m positions rightward. That is, output the result of ...
6k views

### Can you Golf Golf?

You are required to generate a random 18-hole golf course. Example output: [3 4 3 5 5 4 4 4 5 3 3 4 4 3 4 5 5 4] Rules: Your program must output a list of hole ...
8k views

### Shift right by half a bit

The challenge is to implement a program or function (subsequently referred to as "program") that takes a nonnegative integer $n$ as input and returns $n\over\sqrt{2}$ (the input divided by the ...
6k views

### Increment an Array

Given a nonempty array of positive integers, "increment" it once as follows: If all the array elements are equal, append a 1 to the end of the array. For example: ...
950 views

### Sequence of integers not the sum of powers of earlier terms

Starting with 1, output the sequence of integers which cannot be represented as the sum of powers of earlier terms. Each previous term can be used at most once, and the exponents must be non-negative ...
4k views

### Golf a number bigger than Loader's number

As a follow up to Shortest terminating program whose output size exceeds Graham's number and Golf a number bigger than TREE(3), I present a new challenge. Loader's number is a very large number, ...
4k views

### Am I a golfy array?

Definition and Rules A golfy array is an array of integers, where each element is higher than or equal to the arithmetic mean of all the previous elements. Your task is to determine whether an array ...
5k views

### The Rien Number

The Champernowne constant is a number that is constructed by concatenating the first n numbers, with n tending to infinity. It ...
16k views

### Print numbers from 1 to 10

This might be a very simple challenge, but I am surprised it hasn't been done on code-golf yet: Print all Integers from 1 to 10 inclusive in ascending order to standard output. Your output format ...
15k views

### Sum of all integers from 1 to n

I'm honestly surprised that this hasn't been done already. If you can find an existing thread, by all means mark this as a duplicate or let me know. Input Your input is in the form of any positive ...
5k views

### The first n numbers without consecutive equal binary digits

The sequence contains the decimal representation of the binary numbers of the form: 10101..., where the n-th term has n bits. The sequence is probably easiest to ...
3k views

### Numbers in 2050

It's 2050, and people have decided to write numbers in a new way. They want less to memorize, and number to be able to be written quicker. For every place value(ones, tens, hundreds, etc.) the number ...
1k views

### Words with Easy Letters in a Word Search

Introduction: Apparently I keep coming up with word search related challenges lately. :) When I do the word search in the Dutch news paper, some words are very easy to find because they contain ...
2k views

### Machine Epsilon

Machine epsilon is an important floating point number to know when doing numerical calculations. One way to understand it is when this relation ...
10k views

### Determine if all decimal digits are unique

Deleted questions on Stack Overflow sometimes make for great golf material. Write a function that takes a nonnegative integer as input, and returns true if all the digits in the base 10 ...
5k views

### Find the Missing Numbers in the Fibonacci Sequence Mod K

Inspired by this Math.SE question. Background The Fibonacci Sequence (called F) is the sequence, starting 0, 1 such that each ...
1k views

### Average-ignorant sets of integers

Recently a friend of mine posed the following: What subset of the integers satisfies the condition if distinct a and b are in the subset, their average is not in the subset? I know the set of non-0 ...
8k views

### Balanced Ternary Converter

Credits for the challenge idea go to @AndrewPiliser. His original proposal in the sandbox was abandoned and since he has not been active here for several months, I have taken over the challenge. ...
997 views

### Number of complete rhyme schemes

A rhyme scheme is the pattern of rhymes at the end of the lines in a poem. They are typically represented using letters, like ABAB. We consider two rhyme schemes ...
8k views

### Print a bunch of uninteresting numbers!

An uninteresting number (which I totally didn't make up only for this challenge) is created like this: Take a positive integer N Create a new number O by adding the digits of N at the end of N ...
6k views

### Evolution of OEIS

In this challenge, the goal is to recreate the On-Line Encyclopedia of Integer Sequences one sequence at a time. Similar to the Evolution of Hello World, each answer depends on a previous answer. ...
9k views

### Multiply two numbers

Input: Two decimal integers. These can be given to the code in standard input, as arguments to the program or function, or as a list. Output: Their product, as a decimal integer. For example, the ...